JP4402252B2 - Three-dimensional woven braid for composite materials and composite materials - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fiber material and a structural component of a composite material for manufacturing a fiber reinforced resin composite material product having a complicated shape (hereinafter referred to as a fiber reinforced composite material product) at low cost.
[0002]
[Prior art]
In the manufacture of fiber reinforced composite products that are lightweight and tough and have a complex shape, generally, a continuous-type fiber is arranged in one direction, or a semi-cured resin in a woven product. A prepreg, which is a material formed by applying a sheet to form a sheet, is stacked and manufactured according to the shape of the product to be manufactured.
In this case, when there is a straight continuous fiber that is not cut in the middle of the prepreg, particularly in the direction along the continuous fiber, particularly excellent mechanical strength can be obtained, but the product manufactured by stacking the prepregs. The mechanical strength in the thickness direction often depends only on the bonding force of the resin constituting the prepreg, and therefore the mechanical strength in the thickness direction is generally smaller than the in-plate direction reinforced with reinforcing fibers.
[0003]
In order to eliminate such problems and improve the mechanical strength in the thickness direction of the product, a thermoplastic resin is mixed in the surface layer of the prepreg, and the mechanical strength between the materials in the thickness direction is determined by the bonding force of this thermoplastic resin. It has also been proposed to improve strength, that is, toughness, which is the difficulty of breaking fiber reinforced composite products.
For example, in Japanese Patent Application Laid-Open No. 1-110537 “prepreg having spherical fine particles”, spherical thermoplastic resin fine particles are formed on the surface layer of the prepreg within a depth of 30% from the surface of the thickness of each layer formed of the prepreg. Disclosed is to produce a high-strength fiber-reinforced composite product by effectively improving the toughness of the joint surface between prepreg sheets by increasing the localization, increasing the fracture strength at the joint surface of the sheet-like material Has been.
[0004]
However, in order to manufacture products with complicated three-dimensional shapes using prepreg, prepreg is cut out to the required dimensions, and the product shape is divided into simple shape elements and stacked into individual element shapes. It is necessary to perform a preforming process such as a debulk operation that sucks out the air taken in, and even after these simple shape elements are assembled into the final three-dimensional shape of the product, the same operation is performed. This increases the number of product manufacturing steps, requires more work time and labor, and increases the manufacturing cost of the product.
[0005]
On the other hand, continuous fibers are entangled three-dimensionally in three-dimensional directions including the thickness direction in order to overcome the difficulty of developing strength in the thickness direction of fiber-reinforced composite products formed by laminating sheet-like materials. Development of a three-dimensional composite material in which the fiber structure woven and braided into a product shape is solidified with a resin to produce a fiber composite product to reinforce the mechanical strength in the thickness direction is also underway.
However, in order to make such a three-dimensional composite material to reinforce the mechanical strength in any direction and to make a fiber composite product having excellent strength, in particular, a fiber reinforced composite product Requires a dedicated tool and equipment for weaving and braiding a continuous fiber into a three-dimensional fiber structure in accordance with the product shape, and a complex composite fiber composite material. In order to fabricate and fabricate a three-dimensional fiber structure corresponding to a product, a lot of time and labor are required, and there is a problem that the manufacturing cost becomes high as in the case of a prepreg.
A complicated three-dimensional product shape is divided into simple shape elements, and each is formed into a woven braid that is woven and braided three-dimensionally so that the reinforcing fibers are arranged in the thickness direction. However, in this case, the mechanical strength between the woven and braided elements used as the element depends only on the bonding strength of the resin, so it is reinforced with reinforcing fibers. In general, it is lower than the strength of the part.
[0006]
[Problems to be solved by the invention]
In the production of a fiber reinforced composite product having a complicated three-dimensional shape, the present invention eliminates the problems that have occurred in the product manufacturing method that has been conventionally employed. , Prepreg cutting, lay-up work for stacking in the shape of each element, debulking work for sucking out air for each joint of stacked prepregs, etc. There is no need for special tools and equipment for producing woven braided continuous fibers to make a three-dimensional shape that matches the product, and less time and labor for woven braided production. Three-dimensional woven braid for composite materials that can be manufactured at low cost with a complex shape fiber reinforced composite material having sufficient strength, and a structure formed using the woven braid It is an object of the present invention to provide a.
[0007]
[Means for Solving the Problems]
For this reason, the following means was employ | adopted for the fiber raw material of the composite material of this invention.
[0008]
(1) A three-dimensional woven braid for composite materials composed of reinforcing fibers with high elastic strength, which is inferior to reinforcing fibers, but has a high binding force with the resin during integral molding, and is integrated with the reinforcing fibers. A three-dimensional woven braid for composite materials in which fibers with improved binding strength that improve toughness and fracture strength are combined. In the present invention, a three-dimensional woven braid for composite materials composed of reinforcing fibers, in which a binding strength improving fiber is compounded, is a three-dimensional woven fiber woven with a binding strength improving fiber. A woven fabric, a knitted fabric in which a reinforcing fiber is knitted with a reinforcing fiber in a three-dimensional knitted fabric, or a knitted fabric in which a binding strength improving fiber is incorporated in a reinforced fiber in a three-dimensional braid. , Woven fabrics, knitted fabrics or aggregates of reinforcing fibers having the same structure as the braids, and the binding strength improving fibers, and the reinforcing fibers and the binding strength improving yarns are independent yarns. Weaving using yarns that are made simultaneously, such as woven braids, adding reinforcing fibers to the woven braids of reinforcing fiber yarns, or aligning or twisting the reinforcing fiber and binding fiber yarns together Seeds, such as braided Of the use of a woven braid made steps are possible, the procedure of weaving the braid does not matter.
In addition, the binding strength improving fiber is a thickness of each part of the fiber material, from the surface to 1/4 depth of the thickness, or from the surface to the depth of 0.5 mm, whichever is the smaller depth space of the binding strength improving fiber The volume occupancy was set to be greater than the volume occupancy of the binding force improving fibers in the other portions of the fiber material.
[0009]
(A) The three-dimensional woven braid for composite material according to the present invention has the shape of the fiber reinforced composite material product, which has been conventionally required in the preforming step of the prepreg, by using the means of (1) above. The air that is taken into the resin between the prepregs that are divided into two, layup work that cuts and stacks the prepreg according to the shape of each element and stacks each predetermined number of layup work Impregnation and curing work of resin after assembling a simple shape woven braid into a product shape, which eliminates the need for work in the preforming process such as debulking work to suck out, and woven and braided reinforcing fibers and binding strength improving fibers, Since a fiber-reinforced composite material having a product shape can be obtained only by a so-called molding operation, the number of product manufacturing steps can be reduced, working time and labor can be reduced, and manufacturing costs can be reduced.
In addition, it is possible to place particularly many fibers with improved binding strength between the woven braids combined to form a three-dimensional fiber-reinforced composite material product and in the vicinity of the fiber materials. Can be improved.
[0010]
Moreover, the three-dimensional woven braid for composite material of the present invention employs the following means in addition to the above-mentioned means (1).
[0011]
(2) Reinforcing fiber is a high elastic fiber having an elastic modulus of 200 GPa or more, and the binding strength improving fiber is made of a fibrous thermoplastic resin having an elastic modulus of 100 GPa or less. The fracture strength between the braids was improved.
[0012]
(B) The three-dimensional woven braid for composite material according to the present invention is a fiber formed of such a three-dimensional woven braid for composite material in addition to the above (a) by adopting the means of (2) above. Reinforced composite products can have material properties such as breaking strength that are suitable as materials for aerospace, ship, sporting goods, and building in terms of strength, and in particular, weight reduction is required. Products used in the aerospace field have material characteristics that can be significantly reduced in weight, so these woven braids are used in fiber reinforced composite products to improve the performance of aircraft and space equipment manufactured. Can contribute.
[0013]
The three-dimensional woven braid for composite material of the present invention employs the following means in addition to the means (1) or the means (1) and (2).
[0014]
(3) The reinforcing fiber is made of any one of carbon fiber, aramid fiber or glass fiber which is not impregnated with resin or a combination thereof, and the bonding strength improving fiber is polyamide, polyester, polyetheretherketone, polyetherimide or A thermoplastic resin made of any one of polyimides or a combination thereof was made into a fibrous form.
[0015]
(C) The three-dimensional woven braid for composite material according to the present invention is a three-dimensional fiber-reinforced composite material in addition to the above-mentioned (a) or the above-mentioned (a), (b) by using the above-mentioned means (3). The woven braid that forms a product is made of carbon fiber, glass fiber, or aramid fiber, which are high-strength and high-elasticity fibers, and is effective in improving the high-strength and high-elasticity of components. Structural strength and elasticity can be improved.
[0016]
In addition, in the structure of the reinforcing fiber, a bonding strength improving fiber formed of a thermoplastic resin composed of polyamide, polyester, polyetheretherketone, polyetherimide, or polyimide is woven, knitted, or incorporated, The toughness strength at the joint surface between fiber materials can be improved, and the fracture strength of structural parts forming fiber reinforced composite products can be improved. The fracture strength of the joint surface between braids can be improved, and the toughness and strength of fiber reinforced composite products formed by combining these three-dimensional woven braids for composite materials can be improved. Can do.
[0017]
Furthermore, when manufacturing fiber reinforced composite products as a single unit, prepregs are cut out to the required dimensions for each required shape element, stacked in accordance with the manufacturing shape, and debulking operations to extract air between the stacked prepregs. Can be formed, and a three-dimensional fiber-reinforced composite material product having a particularly complicated shape can be formed at a low manufacturing cost.
[0021]
(4) In addition, means or above the above-mentioned (1) of the present invention (1), (2) means or above (1), (2), the composite material for three-dimensional woven braid you means (3) The following means was adopted for the composite material to be formed. After combining a plurality of simple-shaped three-dimensional woven braids obtained by combining reinforcing fibers and bonding strength improving fibers so as to exhibit a desired three-dimensional shape, the reinforcing fibers combined with the three-dimensional shape and the bonding improving fibers A woven braid for composite material made of is impregnated with a resin and molded.
[0022]
( D ) The composite material of the present invention is formed into a product shape by using a three-dimensional woven braid in which reinforcing fibers and binding strength improving fibers are composited by being molded by the means of ( 4 ) above. After combining, by hardening with resin, the toughness strength at the joint surface of the woven braid formed in the fiber reinforced composite product can be improved, and the fracture strength of the fiber reinforced composite product can be improved.
[0023]
In addition, lay-up work that cuts sheet-like materials into the required dimensions for each shape element and stacks them according to the production shape, which was necessary when manufacturing fiber-reinforced composite products with complex shapes using sheet-like materials, and sheets This eliminates the need for pre-molding processes such as debulking to extract air between sheet-shaped materials each time a predetermined number of sheet-shaped materials are stacked, making it a low-cost manufacturing cost and a three-dimensional fiber-reinforced composite with a complicated shape. A material product can be formed and can be a composite material.
[0024]
On the other hand, since a fiber-reinforced composite material product is manufactured by combining a plurality of simple three-dimensional woven braids obtained by combining reinforcing fibers and binding strength improving fibers so as to exhibit a desired three-dimensional shape, In particular, in the case of producing a fiber reinforced composite product having a complicated shape, a dedicated tool that has been conventionally required to produce a three-dimensional fiber structure corresponding to the fiber reinforced composite product having a complicated three-dimensional shape, Equipment is not required, and the time and labor required for weaving and braiding can be reduced, and at low cost, especially in the case of complex-shaped three-dimensional fiber reinforced composite products, in a short time and easily. It can be a composite material that can be formed.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, one embodiment of a three-dimensional woven braid for composite materials and a composite material of the present invention will be described with reference to the drawings.
[0026]
FIG. 1 is a perspective view showing a three-dimensional woven fabric as a first embodiment in an embodiment of a three-dimensional woven braid for composite material of the present invention.
In the figure, reference numeral 1 is a portion constituting a reinforcing material (Reinforcement) of a composite material with reinforcing fibers, and is one of high-strength and high-elastic materials such as carbon fiber, glass fiber or aramid fiber, or a combination of these materials. It is a fiber formed.
Reference numeral 2 denotes a binding strength improving fiber, which is a fiber formed of a material having an effect of improving toughness such as a thermoplastic resin such as polyamide, polyester, polyether ether ketone, polyether imide, or polyimide.
[0027]
After combining the three-dimensional fabric for composite material formed in the three-dimensional fabric 10a with the reinforcing fiber 1 and the binding strength improving fiber 2 described above into the shape of the product, the resin (base material: matrix) is solidified at once. As a result, a fiber-reinforced composite material product having high strength and high breaking strength in which the materials are more firmly bonded can be formed.
[0028]
As described above, the three-dimensional woven fabric is shown as an example. However, it can be configured as a three-dimensional knitted fabric or a three-dimensional braid. The form and structure of the woven braid are not limited as long as it can be constructed at low cost.
For example, a three-dimensional woven fabric woven from a loom capable of forming a fiber structure for an inexpensive and high-performance composite material proposed by the present applicants in Japanese Patent Laid-Open No. 10-325041 “Three-dimensional fiber” is used. It may be made to do.
[0029]
When fibers with improved binding strength are combined inside the structure of a three-dimensional woven braid of reinforcing fibers, not only the bonding surfaces of the materials but also the effect of improving the toughness inside the materials can be obtained. It is also possible to make the entire composite product excellent in breaking strength. Furthermore, especially when the fiber-reinforced composite product has a complex shape, the fiber-reinforced composite product shape required for the prior art is divided into simple-shaped elements, and the lay-up work performed for each element. In addition, it is no longer necessary to perform a pre-molding process such as debulk work, and moreover, the number of product manufacturing processes is increased because only these molding operations are performed after assembling these simple shape elements into a product shape. This eliminates the time and labor involved in reducing the manufacturing cost of the product.
[0030]
Or, compared to the method of weaving and braiding a three-dimensional fiber structure by matching the continuous fiber to the product shape, no dedicated tool equipment is required, and more time is required for making the weaving braid. Similarly, there is an advantage that the manufacturing cost can be reduced.
[0031]
Next, in order to confirm the reinforcing effect between the three-dimensional woven fabric 10a for composite materials according to the first embodiment having the above-described configuration, the results of the joint surface peel strength test between the pedestal portion 5 and the protrusion 6 are performed. explain.
[0032]
FIG. 2 is a diagram showing the principle of this peel strength test.
As shown in the figure, the test material 7 used for the peel strength test is a pedestal part obtained by cutting the above-described 5-axis three-dimensional fabric into a length of 200 m / m, a width of 50 m / m, and a thickness of 1.2 m / m. 5-axis, three-dimensional, using two protrusions 6 cut into a length of 70 m / m, a width of 50 m / m, and a thickness of 1.2 m / m, and solidified with resin at one time (molded with a composite material) Two types of test materials 7 were prepared, one having the bonding strength improving fiber 2 sandwiched between the fabric surfaces and the other having no sandwich.
[0033]
As shown in the figure, the test was supported at a support point 11 provided on the pedestal 5 of the test material 7, and then a load 9 was applied from a load point 8 provided at a position 15 m / m away from the opposite center, The maximum load 9 _{max at} which the protrusion 6 is peeled off from the pedestal 5 is measured as the peel strength.
[0034]
As a result, as shown in FIG. 3, the maximum load 9 _max when the polyimide fiber fiber as the bonding strength improving fiber 2 is not sandwiched between the pedestal portion 5 and the protruding portion 6 is about 31 kgf. However, it was found that when the polyimide fiber fiber was incorporated, it increased to about 35 kgf and the maximum load 9 _max was improved by about 13%.
[0035]
【The invention's effect】
As described above, the three-dimensional woven braid for composite material according to the present invention is a woven material obtained by combining high-strength, high-elasticity reinforcing fibers and bonding strength improving fibers that improve the breaking strength of fiber-reinforced composite products. It was supposed to be braided.
Thereby, the mutual coupling | bonding of the joint surface of the structural components formed combining three-dimensional woven braids for composite materials is reinforced, and the fracture strength of a fiber reinforced composite material product can be improved.
[0036]
Furthermore, when molding complex three-dimensional fiber reinforced composite products, pre-forms such as cutting out prepregs for each simple shape element and stacking them up, stacking a predetermined number of sheets, extracting air between sheets, etc. A process is not required, and a three-dimensional fiber-reinforced composite material product having a complicated shape can be formed at a low manufacturing cost.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a three-dimensional woven fabric as a first form of an embodiment of a three-dimensional woven braid for composite material of the present invention;
FIG. 2 is a schematic diagram showing the principle of a peel strength test of the three-dimensional fabric for composite material shown in FIG.
FIG. 3 is a diagram showing test results obtained in the peel strength test shown in FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Reinforcement fiber 2 Bonding power improvement fiber 5 Base part 6 Protrusion part 7 Test material 8 Load point 9 Load 10a Three-dimensional fabric 11 Support point

Claims (4)

A three-dimensional woven braid for composite materials composed of reinforcing fibers, which is combined with a binding strength improving fiber that has a greater binding strength with the resin integrally molded with the three-dimensional woven braid for composite materials than the reinforcing fibers. The thickness of each part of the fiber material of each part of the three-dimensional woven braid for composite material is from the surface to a depth of 1/4 of the thickness or from the surface to a depth of 0.5 mm, whichever is smaller The three-dimensional woven braid for composite materials, wherein the volume occupancy of the binding force improving fibers in the space is larger than the volume occupancy of the binding strength improving fibers in other parts of the three-dimensional woven braid for composite materials.   The three-dimensional woven braid for composite material according to claim 1, wherein the reinforcing fiber is a fiber having an elastic modulus of 200 GPa or more, and the binding force improving fiber is a fibrous thermoplastic resin having an elastic modulus of 100 GPa or less.   The reinforcing fiber is any one of carbon fiber, aramid fiber, glass fiber, or a combination thereof, and the bonding strength improving fiber is any one of polyamide, polyester, polyetheretherketone, polyetherimide, or polyimide. The three-dimensional woven braid for composite materials according to claim 1 or 2, wherein a thermoplastic resin comprising one or a combination thereof is made into a fiber. A fiber-reinforced composite material obtained by impregnating and curing a resin in a state where the three-dimensional woven braid for composite material according to any one of claims 1 to 3 is combined in a desired product shape.

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